The present invention relates to a safety device for the exposure amount control device, particularly for the exposure amount control device consisting of a camera and an electronic flash device.
Until now flash light photography has been carried out when the object is in darkness. When the electronic flash device is not connected with the current source, or a sufficient output voltage is not maintained even if the electronic flash device is connected with the current source or the flash light device has been repeatedly discharged, the flash light device does not operate or sufficient flash light is not produced when the flash light tube is triggered. p Thus, there exists the shortcoming that when flash light photography is started before a sufficient electrical energy is stored in the storage capacitor, the picture is taken with underexposure so as to cause a waste of film.
Thus, a Japanese Patent Publication Sho 48-6484 has proposed a safety device for the exposure amount control equipment which is so designed that the charge voltage of the storage capacitor of the electronic flash device is detected in such a manner that only when the charge voltage has reached a certain determined value, the shutter is allowed to operate, eliminating the above mentioned shortcoming of the conventional device. However, when the system disclosed in the publication, the shutter is not allowed to operate when the charge voltage of the storage capaciter is lower than a certain determined value so that the improper exposure, namely the waste of film is impossible. On the other hand, every time the flash light photography is started before the charge voltage of the storage capacitor has reached a certain determined value, it is essential to bring various actuated mechanisms such as the mirror driving mechanism, the diaphragm mechanism and so on into the initial state before the shutter release button is pushed down in order to take the next picture. This is inconvenient and the operability is inferior.